Division of Orthopaedic Surgery, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
Section of specialized endocrinology, Oslo University hospital, Oslo, Norway.
J Clin Densitom. 2021 Jul-Sep;24(3):433-441. doi: 10.1016/j.jocd.2020.10.006. Epub 2020 Oct 18.
Dual-energy X-ray absorptiometry (DXA) can measure bone mineral density (BMD) around joint arthroplasties. DXA has never been used in total wrist arthroplasties (TWA). We investigated (1) whether BMD differs between 2 TWAs implanted in the same cadaver forearm, (2) the effect of forearm rotation and wrist extension on measured BMD around TWA in a cadaver, and (3) the precision of DXA in a cadaver and patients.
One ROI around the distal and 1 and 3 ROIs (ROI1-3) around the proximal component were used. Ten DXA scans were performed on forearm and femur mode convertible to orthopedic knee mode without arthroplasty, with ReMotion, and with Motec TWA in one cadaver forearm. Ten scans with 5° increments from 90°-70° pronation and 0°-20° extension, were performed with Motec. Precision was calculated as coefficient of variation (CV%) and least significant change (LSC%) from cadaver scans and double examinations with femur mode converted to orthopedic knee mode in 40 patients (20 ReMotion, 20 Motec).
BMD was higher in all Motec than corresponding ReMotion ROIs (p < 0.05). BMD changed with 10° supination in the distal ROI and ROI1, and with 5° extension in the distal ROI (p < 0.05). In the cadaver the orthopedic knee mode was more precise than the forearm mode in 3 Motec ROIs (p < 0.05). In patients CV was 2.21%-3.08% in the distal ROI, 1.66%-2.01% in the proximal ROI, and 1.98%-2.87% with 3 ROIs.
DXA is feasible for BMD measurement around the proximal component using the orthopedic knee mode, but not the distal component of TWA.
双能 X 射线吸收法（DXA）可测量关节置换周围的骨矿物质密度（BMD）。DXA 从未用于全腕关节置换术（TWA）。我们研究了（1）在同一具尸体前臂中植入的 2 个 TWA 之间 BMD 是否存在差异，（2）在尸体中前臂旋转和腕关节伸展对 TWA 周围测量 BMD 的影响，以及（3）DXA 在尸体和患者中的精确性。
使用一个 ROI 位于远端，1 个和 3 个 ROI（ROI1-3）位于近端组件。在一具尸体前臂中，对无关节置换、ReMotion 和 Motec TWA 分别进行了 10 次 DXA 扫描，这些扫描可在骨科膝关节模式和前臂模式之间转换。在 Motec 上进行了 5°从 90°-70°旋前和 0°-20°伸展的 10 次扫描。从尸体扫描和股骨模式转换为骨科膝关节模式的两次检查中计算出精度，在 40 名患者（20 名 ReMotion，20 名 Motec）中进行了测量。
所有 Motec 的 BMD 均高于相应的 ReMotion ROI（p < 0.05）。在远端 ROI 和 ROI1 中，BMD 随 10°旋后而变化，在远端 ROI 中随 5°伸展而变化（p < 0.05）。在尸体中，骨科膝关节模式比前臂模式在 3 个 Motec ROI 中更精确（p < 0.05）。在患者中，在远端 ROI 中的 CV 为 2.21%-3.08%，在近端 ROI 中的 CV 为 1.66%-2.01%，在 3 个 ROI 中的 CV 为 1.98%-2.87%。
DXA 可使用骨科膝关节模式测量 TWA 近端组件周围的 BMD，但不能测量 TWA 远端组件的 BMD。
